Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS7494638 B1
Publication typeGrant
Application numberUS 07/580,246
Publication dateFeb 24, 2009
Filing dateSep 10, 1990
Priority dateAug 30, 1990
Fee statusPaid
Also published asCA2072117A1, CA2072117C, DE500914T1, DE69128773D1, DE69128773T2, EP0500914A1, EP0500914A4, EP0500914B1, US7473410, US7976813, US8101149, WO1992004279A1
Publication number07580246, 580246, US 7494638 B1, US 7494638B1, US-B1-7494638, US7494638 B1, US7494638B1
InventorsDonald R. Huffman, Wolfgang Krätschmer
Original AssigneeMitsubishi Corporation
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Form of carbon
US 7494638 B1
C60 and C70 carbon atom compounds are prepared by evaporating graphite in an inert quenching gas. The vapor of carbon is collected and is selectively extracted with an organic non-polar solvent.
Previous page
Next page
1. Purified C60.
2. Purified C70.
3. Purified solid C60.
4. Purified solid C70.
5. Crystalline C60.
6. Crystalline C70.
7. Purified crystalline C60.
8. Purified crystalline C70.
9. A macroscopic amount of purified C60.
10. A macroscopic amount of purified C70.
11. A product comprising crystalline C60.
12. A product comprising crystalline C70.
13. A free flowing particulate comprised of crystalline C60.
14. A free-flowing particulate comprising crystalline C70.
15. A solid comprising a macroscopic amount of crystalline C60.
16. A solid comprising a macroscopic amount of crystalline C70.
17. A solid carbon product prepared by the process comprising:
(a) vaporizing a carbon source in the presence of an inert quenching gas under conditions effective to provide a sooty carbon product comprising C60 molecules;
(b) depositing the sooty carbon product on a collecting substrate;
(c) removing the sooty carbon product from the collecting substrate;
(d) contacting the sooty carbon product with a non-polar organic solvent effective to dissolve C60 molecules, said solvent being present in an amount effective to dissolve the C60 molecules in said sooty carbon product; and
(e) recovering from said resulting product formed when the sooty carbon product was contacted with said solvent a solid carbon product comprising C60 in a macroscopic amount.
18. The solid carbon product of claim 17 in which the carbon in step (a) is vaporized in an evacuated reactor.
19. The solid carbon product of claim 18 in which the carbon source of step (a) is vaporized in an evacuated bell jar.
20. The solid carbon product of claim 17 in which the carbon source subject to vaporization in step (a) is graphite.
21. The solid carbon product of claim 17 in which the carbon source subject to vaporization in step (a) is graphite rods.
22. The solid carbon product of claim 17 wherein the carbon source is vaporized in step (a) through heating the carbon source by means of an electrical current of sufficient intensity to produce the sooty carbon product.
23. The solid carbon product of claim 22 wherein the electrical current is about 100 amps.
24. The solid carbon product of claim 17 wherein the inert quenching gas of step (a) is a noble gas.
25. The solid carbon product of claim 17 wherein the carbon source is vaporized in step (a) at a pressure ranging from 50 torr to 400 torr.
26. The solid carbon product of claim 25 wherein the carbon is vaporized in step (a) at approximately 100 torr.
27. The solid carbon product of claim 17 wherein the carbon is vaporized in step (a) at a pressure ranging from about 2 to 3 atmospheres.
28. The solid carbon product of claim 17 wherein the collecting substrate in step (b) is a glass surface.
29. The solid carbon product of claim 24 wherein the inert gas is helium or argon.
30. The solid carbon product of claim 17 wherein the non-polar organic solvent of step (d) is carbon disulfide, benzene, carbon tetrachloride or toluene.
31. The solid carbon product of claim 30 wherein the solvent is benzene.
32. The solid carbon product of claim 30 wherein the solvent is carbon tetrachloride.
33. The solid carbon product of claim 17 wherein recovery step (e) comprises evaporating the solvent.
34. The solid carbon product of claim 17 further comprising C70.
35. The solid carbon product of claim 17, wherein the collecting substrate in step (b) is a glass surface.
36. A solid carbon product prepared by the process comprising:
(a) evaporating a carbon source in the presence of an inert quenching gas under conditions effective to produce a sooty carbon product containing C60, said C60 being present in said sooty carbon product in sufficient concentration to allow a macroscopic amount of said C60 to be separated from said sooty product;
(b) collecting the sooty carbon product produced therefrom;
(c) subliming the carbon product comprising C60 from the sooty carbon product; and
(d) condensing the sublimed carbon product comprising C60.
37. The solid carbon product of claim 36 wherein the sublimation occurs at a temperature ranging from 300°-400° C.
38. The solid carbon product of claim 37 wherein step (c) comprises heating the carbon product comprising C60 in a vacuum or inert atmosphere at effective sublimation temperatures to extract the carbon product comprising C60 from said sooty carbon product.
39. The solid carbon product of claim 36 in which the carbon source in step (a) is vaporized in an evacuated reactor.
40. The solid carbon product of claim 39 in which the carbon in step (a) is vaporized in an evacuated bell jar.
41. The solid carbon product of claim 36 in which the carbon subject to vaporization in step (a) is graphite.
42. The solid carbon product of claim 36 in which the carbon subject to vaporization in step (a) is graphite rods.
43. The solid carbon product of claim 36, wherein the carbon source in step (a) is vaporized by passing an electric current of sufficient intensity to produce a sooty carbon product.
44. The solid carbon product of claim 43, wherein the electrical current is about 100 amps.
45. The solid carbon product of claim 36, wherein the inert quenching gas of step (a) is a noble gas.
46. The solid carbon product of claim 36, wherein the carbon source in step (a) is vaporized at a pressure ranging from 50 torr to 400 torr.
47. The solid carbon product of claim 46, wherein the carbon source is vaporized in step (a) at approximately 100 torr.
48. The solid carbon product of claim 45, wherein the noble gas is helium or argon.
49. The solid carbon product of claim 36, wherein C70 is additionally present.
50. The solid carbon product of claim 49, wherein C70 is separated from C60 by sublimation, column chromatography, fractional crystallization, capillary electrophoresis, preparative thin layer chromatography or extraction.
51. The solid carbon product of claim 49, wherein the C70 is separated from C60 by sublimation.
52. The solid carbon product according to claim 49, wherein the C70 is present in a macroscopic amount.

This is a continuation-in-part of U.S. patent application Ser. No. 07/575,254 that was filed on Aug. 30, 1990, now abandoned.


This invention relates to new forms of carbon as well as methods for the production and recovery thereof from carbon sources.

In 1985, Kroto et al. postulated the existence of a highly stable molecule composed of 60 carbon atoms based solely on mass spectroscopic analysis of vaporized graphite (H. W. Kroto, et al., Nature, Vol. 318, 162, 14 Nov. 1985). More specifically, all that was observed was a peak in the mass spectra of said carbon vapor. However, Kroto et al. did not isolate any of said compound.

A model for this compound was proposed in which 60 carbon atoms are placed at the vertices of a truncated icosahedron forming a perfect “soccerball” structure. Subsequent thereto, many publications have strengthened the evidence for the existence of this molecule. The 60 carbon atom compound (hereinafter C60) was presumably produced in situ for the spectroscopic determination reported in these publications. Yet, to date, no one has been successful in verifying the existence of this molecule since no one has been successful in isolating the molecule in measurable amounts. Thus, no processes for producing recoverable amounts of this new compound have been described to the present time.

In the aforesaid publication by Kroto, et al., the authors proposed many uses for the new substance, C60 if it could be produced in quantity such as C60 transition metal compounds, e.g., C60Fe; or halogenated species like C60F60 which might be a super lubricant; molecules including oxygen and lanthanum in the C60 interior; C60 would provide a topologically novel aromatic nucleus for new branches of organic and inorganic chemistry; and C60 being especially stable and symmetrical provides possible catalyst and/or intermediate in modelling prebiotic chemistry.

Another form of carbon containing 70 carbon atoms (C70) has also been postulated (Kroto, Chemistry in Britain, 40-45 (1990), Kroto, Science, 1139-1145 (1988)). Like the (C60) to date, no one has been successful in verifying the existence of the C70. Heretofore, no one has been successful in obtaining the molecule in any appreciable amounts.


A process has now been developed for the production of recoverable amounts of C60 and C70. The present new process is accomplished by evaporating carbon rods in an atmosphere of an inert quenching gas maintained at reduced pressure in a reactor therefor. This process produces a sooty carbon product which is graphitic carbon including a few percent of C60 and low levels of C70 which are recoverable from the product. However, an increase in the fraction of C70 molecules can be produced if the pressure is raised to greater than atmospheric pressures.

The recovery process is preferably accomplished by selective extraction of C60 and C70 with non-polar organic solvents from the sooty graphitic carbon.

The processes of the present invention produces C60 and C70 in recoverable amounts and permits realization of the proposed uses described hereinbefore.


FIG. 1: micrograph of typical crystals of the 98% C60, 2% C70 material showing thin platelets, rods and stars of hexagonal symmetry.

FIG. 2: X-ray diffraction of a microcrystal-line powder of the 98% C60, 2% C70 solid material. Inset at upper left is a single crystal electron diffraction pattern indexed with Miller indices compatible with the X-ray pattern, taken on a thin platelet as in FIG. 1 with the electron beam perpendicular to the flat face.

FIG. 3: Infrared absorption spectrum of an approximately 2 micrometer thick coating of the 98% C60, 2% C70 material on a silicon substrate, referenced to a clean silicon substrate. Absorption is given as optical density=log10 1/T, where T is transmission. Apparent negative absorptions are due to the coating acting in part as a non-reflecting layer.

FIG. 4: Visible-ultraviolet absorption spectrum of an approximately 0.1 micrometer thick coating of the 98% C60, 2% C70 material on quartz. Shown at the bottom are positions and relative oscillator strengths for allowed transitions calculated for the C60 molecule by Larsson, et al.


The first step in the production of C60 and C70 molecules is vaporizing carbon from any source containing carbon in its various forms, e.g., graphite, amorphous and glassy carbon. It is preferred that this vaporization takes place in an evacuated reactor (e.g., a bell jar). The carbon is vaporized by heating in the presence of an inert quenching gas. The carbon vapor is nucleated in the presence of the inert quenching gas to form smoke particles.

In the production of C60 and C70, any procedure for vaporizing carbon can be used, although the preferred method relies on the use of a high intensity electrical current with graphite rods as electrodes. These rods are constructed to permit vaporization of carbon at the tip of the rod to produce a high density vapor of carbon. For best results, the end of one of the rods is reduced in diameter so that the vaporization occurs at the reduced tip. The rods can be prepared using any of the various forms of carbon, such as graphite, amorphous and glassy carbon.

The inert quenching gas can be any of the usual inert gases such as the noble gas. Argon and helium are preferred, the latter being most preferred. Other inert gases commonly employed to provide a non-reactive atmosphere can also be used as quenching gas.

The amount of C60 and C70 produced from this carbon source is dependent upon the pressure of the quenching gas. At lower pressures relatively pure C60 molecules can be produced in high yield with minor concentrations of C70. For the production of predominantly C60 molecules, the pressure at which the quenching gas is maintained should be subatmospheric and preferably about 50-400 torr. Especially preferred is a pressure of approximately 100 torr. The use of any lower pressure may result in reduced yield of C60.

However, as the pressure is raised, the ratio of C70:C60 is also increased.

If the pressure is increased to at least two atmospheres, the greatest percentage of C70 product is formed. Theoretically, the pressure can be raised to any level just below the point where the reactor would explode from the increased pressure. However, at the higher pressures, the yield of the overall product (C60 and C70) is reduced even though the ratio of C70:C60 is also increased. Therefore, as a practical consideration, the pressure of the quenching gas should not be greater than 10 atmospheres. The preferred pressure for maximizing the amount of C70 produced is 2-3 atmospheres.

The produced quenched vapor of carbon, i.e., the smoked particles coats the internal surface of the reactor and of collecting substrates as black soot. These collecting surfaces are inert to the vaporized carbon. They can be transparent and/or coated with an inert metal. Examples include glass, or gold coated glass surfaces and the like. These collecting surfaces are located in the reactor in the path of the carbon smoke. The black coating can be removed by any suitable means, e.g., by scraping the solids from the coated surfaces. The C60 and C70 molecules can be removed from this collected quenched product by contacting said quenched product with an extracting solvent. In other words, the black soot is placed in a container containing the extracting solvent, or the extracting solvent is poured onto the black soot placed in a container. In either case, the C60 and C70 molecules become dissolved in the solvent, while the remainder of the black soot remains insoluble. The insoluble material is separated from the solution containing the C60 and C70 molecules, e.g., by decanting, or by filtration, and the like.

Suitable solvents include non-polar organic solvents, such as the alkanes containing 5-10 carbon atoms (e.g. pentanes, hexanes, heptanes, octanes), benzene and alkyl-benzenes (e.g. toluene, xylene), carbon disulfide, carbon tetrachloride, naphtha,1,1,1-trichloroethane, and the like. Simple solubility determinations using classical laboratory methods will permit selection of other suitable solvents. The preferred solvents are carbon disulfide, benzene, carbon tetrachloride and toluene. Especially preferred are benzene, carbon tetrachloride and carbon disulfide.

The product obtained contains a mixture of C60 and C70. As described hereinabove, the amounts of C60 and C70 present is dependent upon the pressure used. If subatmospheric pressures are used, such as 50-400 torr, the product is predominatly pure C60 with a minor amount of C70 present. Thus, when the collected product is dispersed in the extracting solvent, the product obtained is a mixture of C60 and C70. For example, when the pressure is 100 torr, the product formed is about 98% C60 and about 2% C70. This product can be separated from the organic solvent solution by standard methods as by evaporation of the solvent or by dilution of the solvent solution with a non-solvent for C60. The product can be crystallized by careful evaporation of the organic solvent or by sublimation procedures.

In a preferred embodiment of producing C60 and C70, pure graphite rods are vaporized by passing high electrical current (either dc or ac) through narrowed tips of graphite rods. Electron beam, laser and RF heating can be used in lieu of electrical heating. This is done in a reactor (such as a bell jar) that has been evacuated, purged and filled with inert gas at or preferably below atmospheric pressure, e.g., pressures ranging from about 50 to about 400 torr. and even higher. The graphite rods are typically ¼ inch in diameter with about 1 cm length of one rod reduced in diameter to about 5 mm. The electrical heating vaporizes the constricted tip of the graphite rod producing a high density vapor of carbon, which quickly condenses into a smoke consisting of very fine particles (of the order of 0.1 microns) of graphitic carbon with an admixture of a few percent of the desired C60 molecule. At this point in the process there is a heavy black coating on collecting substrates and/or on the walls of the chamber which can be easily scraped off for the recovery step.

For recovery, the sooty product is treated with benzene to provide a brownish-red solution. After separation of the undissolved graphitic carbon, the benzene solution is evaporated to obtain microcrystalline product. Alternatively, the product can be sublimed from the sooty carbon at 300° to 400° C. and the sublimation product obtained by condensation on a conventional substrate.

When the pressure of inert quenching gas is 100 torr, the product formed is 98% C60 and 2% C70. This product, as obtained from the solvent extract of the sooty graphitic carbon, is a dark brown to black crystalline material. When obtained by sublimination in vacuum or inert atmosphere, the product is obtained as a brown to gray coating depending on thickness.

On analysis by mass spectroscopy, the spectrum clearly shows a strong peak at mass 720 amu (i.e., the mass of C60) and a clean peak at 840 amu (i.e., the mass of C70). Significant differences in the spectra occur only in the abundances in the mass domain lower than 300 amu. Most of these differences seem to originate from the different ionization techniques in the mass spectrometer and from the different kinds of sample desorption. So far, the cleanest mass spectra have been obtained when the material was evaporated and ionized in the vapor phase by electrons. In such spectra the mass range above 40 amu is dominated by the C60 mass along with its expected isotope lines. The only other large mass found in any abundance corresponds to C60, with a ratio of C70 to C60 of about 0.02.

Studies by optical microscopy of the C60 material which is left after evaporating the benzene solution show a variety of what appear to be crystals—mainly rods, platelets, and star-like flakes. FIG. 1 shows a micro-photograph of such a crystal assemblage. All crystals tend to exhibit six-fold symmetry. In transmitted light they appear red to brown in color; in reflected light the larger crystals have a metallic appearance, whereas the platelets show interference colors consistent with an index of refraction of about 2.

The platelets can be rather thin and thus are ideally suited for electron diffraction studies in an electron microscope. (See the insert in FIG. 2).

In order to determine if the C60 molecules form a regular lattice electron, x-ray diffraction studies on the individual crystals and on the powder were carried out. A typical X-ray diffraction pattern of the purified C60 powder is shown in FIG. 2. To aid in comparing the electron diffraction results with the X-ray results the electron diffraction pattern is inserted into the corner of FIG. 2. From the hexagonal array of diffraction spots indexed as shown in the Figure, a d-spacing of 8.7 Å was deduced corresponding to the (100) reciprocal lattice vector of a hexagonal lattice. The most obvious correspondence between the two types of diffraction is between the 5.01 Å peak of the X-ray pattern and the (100) spot of the electron diffraction pattern, which gives a spacing of about 5.0 Å. Assuming that the C60 molecules are behaving approximately as spheres stacked in a hexagonal close packed lattice with a c/a ratio of 1.633, d-spacings can be calculated. The results are shown in Table I.

X-Ray Diffraction Results and Assignments For a Hexagonal Lattice
Using a = 10.02 Å, c = 16.36 Å
1 d 2 = 4 ( h 2 + h k - k 2 ) 3 ( a 2 ) c 2 + 2
Measured Measured
20 d-spacing Calculated d-spacing
(degrees (Å) (Å) Assignment (hkl)
10.2 shoulder 8.7 8.68 (100)
10.81 8.18 8.18 (002)
7.67 (101)
17.69 5.01 5.01 (110)
20.73 4.28 4.27 (112)
21.63 4.11 4.09 (004)
28.1 3.18 3.17 (114)
30.8 2.90 2.89 (300)
32.7 2.74 2.73 (006)

The values derived from this interpretation are a=20.02 Å and c=16.36 Å. The nearest neighbor distance is thus 10.02 Å. For such a crystal structure the density is calculated to be 1.678 g/cm3, which is consistent with a value of 1.65+/−0.05 determined by suspending crystal samples in aqueous GaCl3 solutions of known densities. Although the agreement shown in Table 1 is good, the absence of the characteristically strong (101) diffraction in hcp and the broad continuum in certain regions suggest a less than perfect crystalline order. Furthermore, X-ray diffraction patterns obtained on carefully grown crystals up to 500 micrometers in size with well developed faces yielded no clear spot pattern (in contrast to the electron diffraction pattern on micron-size crystals). It thus appears that these larger crystals do not exhibit long range periodic order in all directions.

A likely explanation for the unusual diffraction lies in the disordered stacking arrangement of the molecules in planes normal to the c-axis. It is well known that the position taken by spheres in the third layer of stacking determines which of the close-packed structures occurs, the stacking arrangement in fcc being ABCABC while that in hop is ABABAB. If the stacking sequence varies, the X-ray lines due to certain planes will be broadened by the disorder while other lines will remain sharp. Such disordered crystalline behavior was observed long ago in the close packed structure of cobalt, where X-ray diffraction lines such as (101), (102) and (202) were found to be substantially broadened due to the stacking disorder. Reflections from planes such as (002) remain sharp since these planes have identical spacings in both fcc and hcp structures. A general expression for which peaks are broadened by this kind of disorder have been given in terms of Miller indices (h,k,l) as h−k=3t±1, 1≠0, where t is an integer. None of these broadened reflections are apparent in the X-ray pattern of FIG. 2. This may explain the weakness of the characteristically strong (101) peak. Whether or not this stacking disorder is related to the presence of the possibly elongated C70 molecules is yet to be determined.

In small crystals at least, the C60 molecules appear to be assembling themselves into a somewhat ordered array as though they are effectively spherical, which is entirely consistent with the soccer ball hypothesis for their structure. The additional diameter over the calculated 7.1 Å value for the carbon cage itself must represent the effective van der Waals diameter set by the repulsion of the pi electron clouds extending outward from each carbon atom. Scanning tunnelling spectroscopy of the C60 molecules clearly shows the spherical nature of the C60 molecules.

Some scanning tunnelling microscope images of a carbon sample prepared in accordance with the procedure described hereinabove at pressures of helium at 100 torr show a spherical molecule of twice the diameter of the C60 molecules. This is evidence of the existence of a caged molecule containing 240 carbon atoms or a C240 molecule.

Samples were prepared for spectroscopy by subliming pure material onto transparent substrates for transmission measurements. Depending on the pressure of helium in the sublimination chamber, the nature of the coatings can range from uniform films (at high vacuum) to coatings of C60 smoke (i.e., sub-micron microcrystalline particles of solid C60) with the particle size depending to some extent on the pressure.

FIG. 3 shows the transmission spectrum of an approximately 2 micrometer thick C60 coating on a silicon substrate. The infrared bands show the four most intense lines at 1429, 1183, 577, and 528 cm−1, with no underlying continuum remaining from the soot. In early tries at purifying C60 material, the infrared spectrum showed a strong band in the vicinity of 3.0 micrometers, which is characteristic of a CH stretching mode. After much effort, this contaminant was successfully removed by washing the soot with ether and using distilled benzene in the extraction. The spectrum in FIG. 3 was obtained when the material cleaned in such a manner was sublimed under vacuum onto the substrate. The spectrum shows very little indication of CH impurities.

The presence of only four strong bands is what is expected for the free, truncated icosahedral molecule with its unusually high symmetry. Also present are a number of other weak infrared lines which may be due to other causes, among which may be absorption by the C70 molecule or symmetry breaking produced, for example, by isotopes other than C12 in the C60 molecule or by mutual interaction of the C60 molecules in the solid. Noteworthy, are weaker features at about 2330 and 2190 cm−1 which are located in the near vicinity of the free CO2 and CO stretching modes. This may imply some attachment of CO2 or CO to a small fraction of the total number of C60 molecules. Another noteworthy effect can be observed in the feature at 675 cm−1, which is weak in the thin film samples but almost as strong as the four main features in the crystals. This vibrational mode may be of solid state rather than molecular origin.

FIG. 4 shows an absorption spectrum taken on a uniform film coated onto a quartz glass substrate. The ultraviolet features are no longer obscured by the graphitic carbon background as in our previous spectra. Broad peaks at 216, 264 and 339 nm dominate the spectra. Weaker structures show up in the visible, including a plateau with ends at about 460 and 500 nm and a very weak peak near 625 nm. At the bottom of FIG. 4 are shown positions and relative oscillator strengths taken from Larsson, et al. (Chem. Phys. Lett. 137, 501-504) calculated for the C60 molecule. This reference also shows a variety of forbidden bands with the lowest energy ones in the vicinity of 500 nm. There seems to be a rough correspondence between the present measurements on thin films and the allowed transitions predicted for the molecule. There was no band at 386 nm in our films of C60, a disclosed by Heath, et al. (J. Chem. Phys. 87, 4236-4238 (1987)) using a laser depletion spectroscopy method and attributed to the C60 molecule. Quite similar spectra to that in FIG. 4 have been recorded for microcrystalline coatings deposited at helium pressures of 100 torr, for example. The peaks occur at the slightly shifted positions of 219, 268, and 345 nm.

The C70 molecule is larger than the C60 molecule. The C70 molecule shows a molecular ion peak at 840 amu. Furthermore, a noticeable peak in the ultraviolet spectrum of the C70 molecule taken on a uniform film coated onto a quartz glass substrate is exhibited at about 216 nm. This is a broad peak. Surprisingly, it appears that the C70 molecule is more stable than C60.

Thus, using the procedures described hereinabove, at quenching pressures of less than 1 atmospheric pressure and especially at pressures of 50-400 torr, a product is produced which is predominantly C60 and contains minor amounts of C70. The C60 product can be used or can be further purified.

Further purification and separation of C60 and C70 can be made by many conventional techniques known to one skilled in the art, e.g., fractional crystallization, column chromatography, capillary electrophoresis, HPLC, preparative thin-layer chromatography, and the like.

Because the molecular figuration of C60 and C70 are different, the attractive intermolecular forces are different which allows for the two molecules to be readily separated.

Furthermore, the solubility of C60 and C70 in pure solvents and mixed solvents are also different from each other, which also makes the two compounds separable by using conventional techniques known to one skilled in the art, such as crystallization, extraction, and the like.

For example, pure C60 and pure C70 molecules can be isolated as follows. The black sooty mixture of C60 and C70 which is produced according to the procedure described hereinabove is placed in the extracting solvent, such as benzene. The insoluble residue is removed and the resulting benzene solution containing C60 and C70 molecules is concentrated. The C60 and C70 solution is added to a packed column with an adsorbent, such as alumina. The column is eluted with an eluent such as benzene or a mixture of benzene and toluene. Various fractions of set volume e.g., 10 mL, are collected. The eluent i.e., the solvent is removed from each fraction such as by evaporation to dryness. The fractions with product will contain microcrystals, the identity of which can be confirmed by spectroscopy, e.g., mass spectroscopy.

Thus, the process of the present invention can produce a product which is predominantly C60, which, if desired, can be further purified by the purification and separation techniques described hereinabove.

Furthermore, the present invention contemplates two different variations of the procedure described hereinabove to make C70 molecules. First, if subatmospheric pressures of quenching gases are used in the initial step, small amounts of C70 are produced, which can be separated from the C60 molecules using the purification techniques described hereinabove. However, if the pressure of the quenching gas is raised to at least 2 atmospheres, after separation and purification, a greater percentage of substantially pure C70 would be produced from each vaporization of carbon.

The present new products, C60, C70, or mixtures thereof have the similar utilities as graphite. However, they are particularly valuable for forming products of a higher order of stability than those formed from graphitic carbon, and can be processed into formed or molded products such as C60 fibers, C70 fibers, or mixtures thereof using standard processing techniques. In this regard, free-flowing, particulate C60 and C70 are of special value particularly for use in producing molded products, especially those extended in at least one direction. C60, and C70 are also useful for producing a low temperature C60 vapor (300°-400° C.) and C70 vapor of the respective molecules to produce low temperature atomic and molecular beams of carbon which is not now possible using graphite as the carbon source. Further, the synthesis of compounds such as C60H60 and C60F60 can be accomplished by introducing hydrogen and fluorine, respectively, into a reactor containing C60 vapor. Furthermore, the C60 product and the C70 product may be used as an industrial paint pigment or as a lubricant. Moreover, since the C60 and C70 molecule are hollow, they could be used for binding and/or storing molecules e.g., toxic material.

Example 1

C60-containing carbon dust was produced in a conventional bell-jar carbon evaporator which was first evacuated to 10−4 torr by either an oil diffusion pump or a turbo pump, both equipped with liquid nitrogen traps, and then filled with an inert quenching gas. Helium and argon were used at pressures ranging up to 400 torr. Then graphite rods (as previously described herein) were evaporated using a current of about 100 amps (either AC or DC).

The smoke which formed in the vicinity of the evaporating carbon rods was collected on substrates which were placed within 5 cm to 10 cm of the evaporating carbon rods.

The evaporator was opened after a cool down period of 10-30 min. and the carbon dust samples removed by scraping substrate surfaces and the internal surfaces of the bell-jar. After washing with ether, the collected dust samples were then extracted with benzene to produce a wine-red to brown solution. On evaporation of the solution, C60 was obtained as a microcrystalline residue.

The crystals were sublimed by heating in vacuo or in a quenching inert gas to 400° C. and collected on a substrate. The sublimed product was brown to gray in color.

In powder form, the present new carbon allotrope is brownish-red.

Example 2

The procedure of Example 1 is repeated except, in the original step, the graphite rods are evaporated at 2 or more atmospheres of helium pressure in the chamber. The product obtained from this procedure contains a greater percentage of C70 than does the product in Example 1.

Example 3

Pure C60 and pure C70 are obtained as follows:

The C60 and C70 mixtures prepared in either Examples 1 or 2 are dissolved in benzene and added to an alumina column. Using benzene as the eluent, the fractions are collected and each elute fraction is evaporated to dryness. The presence of C60 or C70 in the fraction can be determined by taking mass spectroscopy thereof.

The above embodiments and examples are given to 1 illustrate the scope and spirit of the instant invention.

These embodiments and examples are within the contemplation of the present invention. Therefore, the present invention should be limited only by the appended claims.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4132671Nov 30, 1977Jan 2, 1979Veba-Chemie AktiengesellschaftExtracting aggregation with oils, fats, waxes and distillation residues from gasification
US5114477 *Sep 3, 1991May 19, 1992Xerox CorporationLiquid ink compositions
US5132105 *Aug 31, 1990Jul 21, 1992Quantametrics, Inc.Materials with diamond-like properties and method and means for manufacturing them
US5227038 *Oct 4, 1991Jul 13, 1993William Marsh Rice UniversityCarbon vaporization, plasma
US5234474 *Jun 19, 1991Aug 10, 1993Whewell Christopher JInternal combustion engines
US5273729 *May 24, 1991Dec 28, 1993Massachusetts Institute Of TechnologyMacroscopic amounts obtained by combustion of a carbon fuel using a controlled amount of oxygen, an oxidant and diluent
SU1587000A1 * Title not available
Non-Patent Citations
1Aihara, et al., Spherical Aromaticity of Buckminsterfullerene, Bull. Chem. Soc. Jpn. 61, (1988) pp. 2657-2659.
2 *Akhter et al, The Structure of Hexame Scot II: Extraction Studies, Applied Spectroscopy , vol. 39, No. 1, 1955, pp. 154-167.
3Almlof, et al:, Theoretical Methods and Rsults for Electronic Structure Calculations on Very Large Systems Carbon Clusters, ACS Symposium Series 353, 1987, pp. 35-48.
4 *Amato, "A First Sighting of Buckyballs in the Wild," Science, vol. 257, No. 5067, Jul. 10, 1992, p. 117.
5Balasubramanian, et al., Computer Generation of Spectra of Graphs: Applications to C60 Clusters and Other Systems, Journal of Computational Chemistry, vol. 9, No. 4, (1988) pp. 406-415.
6Ballester, et al., Atoms in Carbon Cages as a Source of Interstellar Diffuse Lines, The Astrophysical Journal 356 pp. 507-512, Jun. 20, 1990.
7 *Blav et al. "An Investigation of the Microfrictional Behavior of C60 Particle Layers on Aluminum" Thin Solio Films, 219 pp. 129-134 Oct. 30, 1993.
8Bloomfield, et al., Negative and Positive Cluster Ions of Carbon and Silicon, Chemical Physics Letters, vol. 121, No. 1,2, Nov. 1, 1985, pp. 33-37.
9Bochvar, et al., Problems in the Structural Chemistry of Crystallne Carbon, Sov. Sci. Rev. B. Chem., vol. 9, 1987, pp. 483-527.
10Brendsdal, et al., Normal Coordinate Analysis of "Footballene" C60, Spectroscopy Letters, 21(4), 1988, pp. 313-318.
11Brendsdal, Symmetry Coordinates of Molecular Vibrations of "Footballene" C60, Spectroscopy Letters, 21(4), 1988, pp. 319-339.
12Brown, High Symmetries in Quantum Chemistry, Chemical Physics Letters, vol. 136, No. 2, May, 1987, pp. 128-133.
13 *Buseck et al., "Fullerenes From the Geological Envirnoment," Science, vol. 257, No. 5067, Jul. 10, 1992 pp. 215-217.
14Campbell, et al., An intense, simple carbon cluster source, J. Chem. Phys. 93(9), Nov. 1, 1990, pp. 6900-6907.
15Ceulemans, et al., SO(4) symmetry and the static Jahn-Teller effect in icosahedral molecules, Physical Review A, vol. 39, No. 2, Jan. 15, 1989, pp. 481-493.
16Ceulemans, et al., The Jahn-Teller instability of fivefold degenerate states in icosahedral molecules, J. Chem. Phys. 93(2), Jul. 15, 1990, pp. 1221-1234.
17Cox, et al., C60La: A Deflated Soccer Ball?, J. Am. Chem. Soc. 1986, 108, pp. 2457-2458.
18Creasy, et al., Formation of high mass carbon cluster ions from laser abiation of polymers and thin carbon films, J. Chem. Phys. 92(4) Feb. 15, 1990, pp. 2269-2277.
19Creasy, Some model calculations of carbon cluster growth kinetics, J. Chem. Phys. 92(12), Jun. 15, 1990, pp. 7223-7233.
20 *Curl et al. Scientific American, Oct. 1991, pp. 54-63.
21Curl, et al., Probing C60, Science, vol. 242, Nov. 18, 1988, pp. 1017-1022.
22Dias, A Facile Huckel Molecular Orbital Solution of Buckminsterfullene Using Chemical Graph Theory, Journal of Chemical Eduction, vol. 66, No. 12, Dec. 1989 pp. 1012-1015.
23Dietz, et al., Laser production of supersonic metal cluster beams, J. Chem. Phys. 74(1), Jun. 1, 1981, pp. 6511-6512.
24Disch, et al., On Symmetrical Clusters of Carbon Atoms: C60, Chemical Physics Letters, vol. 125, No. 5,6, Apr. 18, 1986, pp. 465-466.
25Elser, et al., Icosahedral C60:an aromatic molecule with a vanishingly small ring current magnetic susceptibility, Nature vol. 325, Feb. 26, 1987, pp. 792-794.
26Elser, et al., Magnetic behavior of icosahedral C60, Physical Review A General Physics Third Series, vol. 36, No. 10, Nov. 15, 1987, pp. 4579-4585.
27 *Fang et al., "Evidence for fullerene in a coal of Yunnan, South western China", Mat. Res. Innovat. (1997), pp. 130-132.
28Fowler, et al., Electric and Magnetic Properties of the Aromatic Sixty-Carbon Cage, Chemical Physics Letters, vol. 165, No. 1, Jan. 5, 1990, pp. 79-86.
29Fowler, et al., pi-Systems in Three Dimensions, Chemical Physics Letters, vol. 127, No. 1, May 30, 1986, pp. 78-83.
30Fowler, et al., Systematics of Bonding in non-icosahedral carbon clusters, Theor Chim Acta (1988) 73: pp. 1-26.
31Fowler, et al:, The Leapfrog Principle: A Rule for Electron Counts of Carbon Clusters, J. Chem. Soc., Chem. Commun., 1987 pp. 1403-1405.
32Fowler, How Unusual is C60? Magic Numbers for Carbon Clusters, Chemical Physics Letters, vol. 131, No. 6, Nov. 21, 1986, pp. 444-450.
33 *Fritsch, 'Colour and Colour Changes in Diamonds' in Gemmologist vol. 17 #209 p. 328. Dec. 1948.
34 *Gerhardt et al, Chemical Physics Letters, vol. 137, No. 4, pp. 306-310, Jun. 19, 1987.
35Gerhardt, et al., Polyhedral Carbon Ions in Hydrocarbon Flames, Chemical Physics Letters, vol. 137, No. 4, Jun. 19, 1987, pp. 306-310.
36Haddon, et al., Electronic Structure and Bonding in Icosahedral C60, Chemical Physics Letters, vol. 125, No. 5,6, Apr. 18, 1986, pp. 459-464.
37Haddon, et al., Icosahedral C60 Revisited: An Aromatic Molecule with a Vanishingly Small Ring Current Magnetic Susceptibility, Chemical Physics Letters, vol. 169, No. 4, Jun. 8, 1990, pp. 362-364.
38Haddon, et al., Rehybridization and pi-Orbital Alignment: The Key to the Existence of Spheroidal Carbon Clusters, Chemical Physics Letters, vol. 131, No. 3, pp. 165-169, (1986).
39Hahn, et al., Magic Numbers in C+N and CN Abundance Distributions, Chemical Physics Letters, vol. 130, No. 1,2, Sep. 26, 1986, pp. 12-16.
40Hale, Discrete-Variational-X alpha Electronic Structure Studies of the Spherical C60 Cluster: Prediction of Ionization Potential and Electronic Transition Energy, J. Am. Chem. Soc. 1986, 108, pp. 6087-6088.
41Harano, et al., Decomposition of gaseous hydrocarbons in a laser-induced plasma as a novel carbonaceous source for cluster formation, Chemical Physics Letters, vol. 172, No. 3,4 Sep. 7, 1990, pp. 219-223.
42Harter, et al., Rotation-vibration spectra of icosahedral molecules. I. Icosahedral symmetry analysis and fine structure, J. Chem. Phys. 90(9), May 1989, pp. 4727-4743.
43Harter, et al., Rovibrational Spectral Fine Structure of Icosahedral Molecules, Chemical Physics Letters, vol. 132, No. 4,5, Dec. 19, 1986, pp. 387-392.
44Hayden, et al., pibonding in the icosahedral C60 cluster, Physical Review B, vol. 36, No. 9, Sep. 15, 1987, pp. 5010-5015.
45Haymet, C120 and C60: Archimedean Solids Constructed from sp2 Hybridized Carbon Atoms, Chemical Physics Letters, vol. 122, No. 5, Dec. 20, 1985, pp. 421-424.
46Haymet, Footballene: A Theoretical Prediction for the Stable, Truncated Icosahedral Molecule C60, J. Am. Chem. Soc. 1986, 108, pp. 319-321.
47Heath, et al., Lanthanum Complexes of Spheroidal Carbon Shells, J. Am. Chem. Soc., 1985, 107, pp. 7779-7780.
48Hess, Jr., et al., The Stability of Footballene, J. Org. Chem, 1986, pp. 3902-3903.
49 *Howard et al, Nature, vol. 352, pp. 139-141, Jul. 11, 1991.
50 *J. Lefevre, "Investigation of Iron and Carbon Dusts," Annales D'Astrophysique, vol. 30, No. 4, pp. 731-738, 1967.
51Jelski, et al., Clusters: Link between Molecules and Solids, Journal of Chemical Education, vol. 65, No. 10, Oct. 1988, pp. 879-883.
52Joblin, et al., Detection of diffuse interstellar bands in the infrared, Nature, vol. 346, Aug. 23, 1990, pp. 729-731.
53Kaldor, et al., Molecular Surfaces: Chemistry and Physics of Gas Phase Clusters, Microclusters: Proceedings of the First NEC Symposium, 1987, pp. 96-106.
54 *Kappler et al., J. Appl. Phys. 50 (1), 1979, pp. 308-316.
55Kataoka, et al., Geometrical Structures and Spectra of Corannulene, and Icosahedral C60 Tetrahedron, vol. 42, No. 23, pp. 6437-6442, (1986).
56 *Kirk-Othmer Encyclopedia of Chemical Technology, 3d Ed., vol. 4, John Wiley-Sons, 1978, pp. 652-653.
57Klein, et al, Resonance in C60 Buckminsterfullerene, J. Am. Chem. Soc. 1986, 108, pp. 1301-1302.
58Klein, et al., Icosahedral symmetry carbon cage molecules, Nature, vol. 323, Oct. 23, 1986, pp. 703-706.
59Kovacevic, et al. On the Hybridization in Some Archimedean Carbon Clusters, International Journal of Quantum Chemistry Symposium 21, (1987) pp. 589-593.
60 *Kratschmer et al. Surface Science vol. 156, pp. 814-821, 1985.
61 *Kratschmer et al., "Search for the UV and IR Spectra of C60 in Laboratory-Produced Carbon Dust," in Dusty Objects in the Universe (Netherlands, Kluwer Academic Publishers, 1990, E. Bussoletti and A.A. Vittone (eds.)), pp. 89-93).
62Kratschmer, et al., The infrared and ultraviolet absorption spectra of laboratory-produced carbon dust: evidence for the presence of the C60 molecule, Chemical Physics Letters, vol. 170, No. 2,3, Jul. 6, 1990.
63 *Kroto et al., Nature, vol. 318, pp. 162-163, 1985.
64Kroto, et al., C60: Buckminsterfullerene, Nature, vol. 318, Nov. 14, 1985, pp. 162-163.
65Kroto, et al., The formation of guasi-icosahedral spiral shell carbon particles, Nature, vol. 311, Jan. 28, 1988, pp. 328-331.
66Kroto, Giant fullerenes, Chemistry in Britain, Jan. 1990, pp. 40-43.
67Kroto, Giant fullerenes, Chemistry in Britain, Jan. 1990, pp. 40-45.
68Kroto, Space, Stars, C60 and Soot, Science, vol. 242, Nov. 25, 1988, pp. 1139-1145.
69Kroto, Space, Stars, C60, and Scot, Science, Nov. 25, 1988, pp. 1139-1145.
70Kroto, The chemistry of the interstellar medium, Phil. Trans. R. Soc. Lond. A 325, 1988, pp. 405-421.
71Kruto, Chains and Grains in Interstellar Space, Polycyclic Aromatic Hydrocarbons and Astrophysics, pp. 197-206 (1987).
72Larsson, et al., Optical Spectrum of the Icosahedral C60-"Follene-60", Chemical Physical Letters, vol. 137, No. 6, Jul. 3, 1987, pp. 501-503.
73Laszlo, et al., On the Geometricial Structure and UV Spectrum of the Truncated Icosahedral C60 Molecule, Chemical Physics Letters, vol. 136, No. 5, May 15, 1987, pp. 418-422.
74Lefevre, An Experimental Study of the Dust of Iron, CArbon, Silicon Carbide and Silica, Astron. & Astrophys. vol. 5, No. 1, 1970 pp. 37-44.
75Leger, et al., Identification of the unidentified IR emission features of interstellar dust? Astron. Astrophys. 137, (1986), pp. L5-L8.
76Leger, et al., Remarkable candidates for the carrier fo the diffuse interstellar bands: C60+ and other polyhedral carbon ions, Astron. Astrophys., 203, (1988) pp. 145-148.
77 *Liu et al., "Experimental Results on High Yield C70 Fullerene," Chin. Phys. Lett, vol. 11, No. 10 (1994), pp. 609-610.
78Liu, et al., Negative Carbon Cluster Ion Beams: New Evidence for the Special Nature of C60, Chemical Physics Letters, vol. 126, No. 2, May 2, 1986, pp. 215-217.
79Luthi, et al., Ab Initio Studies on the Thermodynamic Stability of the Icosahedral C60 Molecule "Buckminsterfullerene", Chemical Physics Letters, vol. 135, No. 4,5, Apr. 10, 1987 pp. 357-360.
80Marynick, et al., Localized Molecular Orbitals and Electronic Structure of Buckminsterfullerene, Chemical Physics Letters, vol. 132, No. 4,5, pp. 383-386, (1986).
81McElvany, et al., Ion-molecule reaction studies of mass selected carbon cluster ions formed by laser vaporization, J. Chem. Phys. 85(1), Jul. 1, 1986, pp. 632-633.
82McKee, et al., Calculated Properties of C60 Isomers and Fragments, Journal of Molecular Structure (Theochem:), 153 (1987) pp. 75-84.
83Negri, et al., Quantum-Chemical Investigation of Frank-Condon and Jahn-Teller Activity in the Electronic Spectra of Buckminsterfullerene, Chemical Physics Letters, vol. 144, No. 1, Feb. 12, 1988, pp. 31=36.
84Newton, et al., Stability of Buckminsterfullerene and Related Carbon Clusters, J. Am. Chem. Soc., 1986, 108, pp. 2469-2470.
85O'Brien, et al., Photophysics of Buckminsterfullerene and other carbon cluster ions, J. Chem. Phys. 88(1), Jan. 1, 1988, pp. 220-230.
86O'Keefe, et al., Production of Large Carbon Cluster Ions by Laser Vaporization, Chemical Physics Letters, vol. 130, No. 1,2, Sep. 26, 1986, pp. 17-19.
87 *Osawa et al., "Survey of Natural Fullerenes in Southwestern China", pp. 421-424 in Nanonetwork Materials, edited by S. Saito et al., 2001, American Institute of Physics.
88Ozaki, et al., On Electronic States and Bond Lengths of the Truncated Icosahedral C60 Molecule, Chemical Physics Letters, vol. 127, No. 3, Jun. 13, 1986, pp. 242-244.
89Pussoletti, et al., Experiemtns on Cosmic Dust Analogues, vol. 149 Proceedings, pp. 25-42, 1987.
90Rabilizirov, The Role of Cavities and Mantles in the Ultraviolet Extinction Peak of Graphite Spheres with Particular Reference to a Possibly Discovered C60 Structure, Astrophysics and Space Science 125 (1986), pp. 331-339.
91Randic, et al., On the Aromatic Stability of a Conjugated C60 Cluster, Croatica Chemical ACTA 60 (4) 1987 pp. 595-604.
92 *Rietmeijer et al., "C60 and Giant Fullerenes in Soot Condensed in Vapors with Vapors with Variable C/H2 Ratio", Fullerenes, Nanotubes, and Carbon Nanostructures, vol. 12, No. 3, pp. 659-680, 2004.
93Rohlfing, et al., Productin and characterization of supersonic carbon cluster beams, J. Chem. Phys. 81(7), Oct. 1, 1984, pp. 3322-3330.
94Rohlfing, et al., Two-color pyrametric imaging of laser-heated carbon particles in a supersonic flow, Chemical Physics Letters, vol. 170, No. 1, Jun. 29, 1990, pp. 44-50.
95Rosen, et al., Calculations of the ionization thresholds and electron affinities of the neutral, positely and negatively charged C60-"follene-60", J. Chem. Phys. 90(4), Feb. 15, 1989, pp. 2525-2526.
96Rosen, et al., First-Principle Calculations of the Ionization Potentials and Electron Affinities of the Spheroidal MoleculesC60 and LaC60, J. Am. Chem. Soc., 1988, 110, pp. 8701-8703.
97Rosen, et al., Optical Spectrum ofthe Icosahedral C60-"Follene-60": A Challenge for Laser Spectroscopy, Laser Spectroscopy VIII, Proceedings of the Eighth International Conference, Jun. 1987, pp. 250-253.
98Rudzinski, et al., Corrputation Study of Relative Stabilities of C60(Ih) and C70(D5h) Gas-Phase Cluters, Thermochimica Acta, 125 (1988) pp. 155-162.
99Satpathy, Electronic Structure of the Truncated-Icosahedral C60 Cluster, Chemical Physics Letters, vol. 130, No. 6, Oct. 24, 1986, pp. 545-550.
100Schmalz, et al., Elemental Carbon Cages, J. Am. Chem. Soc. 1988, 110, pp. 1113-1127.
101Schulmen, et al., Symmetrical Clusters of Carbon Atoms: the C24 and C60 Molecules, Chemical Physics Letters, vol. 141, No. 1,2, Oct. 30, 1987 pp. 45-48.
102Scott, et al., Benzene Ring Contractions at High Temperatures, Evidence from teh Thermal Interconversions of Aceanthrylene, Acephenanthrylene, and Fluoranthene, J. Am. Chem. Soc. 1987, 109, pp. 5461-5465.
103Shibuya, et al., Two-Icosahedral Structures for the C60 Cluster, Chemical Physics Letters, vol. 137, No. 1, May 29, 1987, pp. 13-16.
104 *Sinknkas, Gemstone & Mineral Data Book, Wihdiester Press 1979. p. 116.
105Slanina, et al., C60(g), C70(g), Saturated Carbon Vapour and Increase of Cluster Populations with Temperature: A Combined Aml Quantum-Chemical and Statistical-Mechanical Study, Collection Czechoslavak Chem. Commun. vol. 52, (1987) pp. 2831-2839.
106Stankevich, et al., The Structural Chemistry of Crystalline Carbon: Geometry, Stability, and Electronic Spectrum, Russian Chemical Reviews, 53(7), 1984, pp. 640-655.
107Stanton, et al., Normal Vibrational Modes of Buckminsterfullerene, J. Phys. Chem., 1988, 92, pp. 2141-2145.
108Stone, et al., Theoretical Studies of Icosahedral C60 and Same Related Species, Chemical Physics Letters, vol. 128, No. 5,6, Aug. 8, 1986, pp. 501-503.
109The Condensed Chemical Dictionary, 10th Ed., Revised by Gessner G. Hawley, p. 871 (1981).
110 *Translation for J. Lefevre, "Investigation of Iron and Carbon Dusts," Annales D'Astrophysique, vol. 30, No. 4, pp. 731-738, 1967.
111Vinokur, et al., Measured Extinction Efficiency of Graphite Smoke in the Region 1200-6000A, Nature Physical Science, vol. 243, May 21, 1973, pp. 50-51.
112Wales, Closed-Shell Structures and the Building Game, Chemical Physics Letters, vol. 141, No. 6, Nov. 27, 1987, pp. 478-484.
113Weeks, et al., Rotation-vibration spectra of icosahedral molecules. II. Icosahedral symmetry, vibrational eigenfreguencies, and normal modes of buckminsterfullerene, J. Chem. Phys. 90(9), May 1989 pp. 4744-4771.
114Williams, Close packing of spheres, J. Chem. Phys. 87(7), Oct. 1, 1987 pp. 4206-4211.
115Wu, et al., Vibrational Motions of Buckminsterfullerene, Chemical Physical Letters, vol. 137, No. 3, Jun. 12, 1987 pp. 291-294.
116Wu, et al., Vibrational Motions of Buckminsterfullerene, Chemical Physics Letters, vol. 137, No. 3, Jun. 12, 1987, pp. 291-294.
117Yang, et al., Ups of 2-30-Atom Carbon Clusters: Chains and Rings, Chemical Physical Letters, vol. 144, No. 5,6, pp. 431-436, Mar. 11, 1988.
118Yang, et al., Ups of Buckminsterfullerene and Other Large Clusters of Carbon, Chemical Physics Letters, vol. 139, No. 3,4, Aug. 28, 1987 pp. 233-239.
119Zhang, et al., Reactivity of Large Carbon Clusters: Spheroidal Carbon Shells and their Possible Relevance to the Formation and Morphology of Soot, The Journal of Physical Chemistry, vol. 90, No. 4, Feb. 13, 1986, pp. 525-528.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US8182783 *Nov 16, 2006May 22, 2012New Jersey Institute Of TechnologyRapid microwave process for purification of nanocarbon preparations
US8323606 *Dec 3, 2004Dec 4, 2012Industrial Technology Research InstituteHetero-nanocapsule and method of preparing the same
US20080060581 *Oct 30, 2007Mar 13, 2008Pfeiffer Loren NDeposition of carbon-containing layers using vitreous carbon source
U.S. Classification423/445.00B, 977/735, 977/844, 977/845
International ClassificationB82B1/00, C01B31/02, C01B31/00, B82B3/00
Cooperative ClassificationY10S977/845, Y10S977/735, Y10S977/844, B82Y40/00, B82Y30/00, C01B31/0206
European ClassificationB82Y30/00, B82Y40/00, C01B31/02B
Legal Events
Jul 25, 2012FPAYFee payment
Year of fee payment: 4
Dec 26, 2007ASAssignment
Effective date: 20071128
Feb 14, 2001ASAssignment
Effective date: 19991203